Tailsitter unmanned aerial vehicles are utilized extensively nowadays since they merge advantages of both fixed-wing unmanned aerial vehicles and rotary-wing unmanned aerial vehicles. However, their attitude control suffers from unknown nonlinearities and disturbances due to the wide flight envelope. To solve the problems, a robust attitude controller based on a newly designed flying-wing tailsitter is proposed in this paper. By employing the angular acceleration feedback to compensate unmodeled dynamics, the proportional incremental nonlinear dynamic inversion control law is first developed. The proportional incremental nonlinear dynamic inversion strengthens the conventional nominal gain incremental nonlinear dynamic inversion with a proportional term to reflect the change of the angular acceleration more directly. Therefore, the tailsitter has a quicker response and performs better in suppressing model uncertainties and external disturbances. Since the angular acceleration is difficult to measure in practice, an angular acceleration estimation method is then established to provide accurate signals for the proportional incremental nonlinear dynamic inversion. The signals are derived as complementary results of model prediction method and direct differential method. Theoretical analysis and systematic simulations are conducted to corroborate the effectiveness of the developed estimation method as well as the robustness of the proposed controller.

中文翻译：

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飞翼尾翼的鲁棒比例增量非线性动态反演控制

尾翼无人机融合了固定翼无人机和旋翼无人机的优点，如今被广泛使用。然而，由于飞行包线较宽，它们的姿态控制受到未知的非线性和干扰。为了解决这些问题，本文提出了一种基于新设计的飞翼尾翼的鲁棒姿态控制器。通过使用角加速度反馈来补偿未建模的动力学，首先开发了比例增量非线性动态反演控制律。比例增量非线性动态反演加强了传统的标称增益增量非线性动态反演，增加了一个比例项，更直接地反映角加速度的变化。所以，tailsitter 响应更快，在抑制模型不确定性和外部干扰方面表现更好。由于实际中角加速度难以测量，因此建立角加速度估计方法，为比例增量非线性动态反演提供准确的信号。这些信号是作为模型预测方法和直接微分方法的互补结果导出的。进行理论分析和系统模拟以证实所开发的估计方法的有效性以及所提出的控制器的鲁棒性。然后建立角加速度估计方法，为比例增量非线性动态反演提供准确的信号。这些信号是作为模型预测方法和直接微分方法的互补结果导出的。进行理论分析和系统模拟以证实所开发估计方法的有效性以及所提出控制器的鲁棒性。然后建立角加速度估计方法，为比例增量非线性动态反演提供准确的信号。这些信号是作为模型预测方法和直接微分方法的互补结果导出的。进行理论分析和系统模拟以证实所开发的估计方法的有效性以及所提出的控制器的鲁棒性。